by Chuo University

edited by Sadie Harley, reviewed by Robert Egan

Led by Assistant Professor Kou Li, a research group at Chuo University, Japan, has developed a synergetic strategy among non-destructive terahertz (THz)¨Cinfrared (IR) photo-monitoring techniques and ultrabroadband sensitive imager sheets toward demonstrating in-line real-time multi-scale quality inspections of pharmaceutical agent pills.

The paper has been published in Light: Science & Applications.

While non-destructive in-line monitoring at manufacturing sites is essential for safe distribution cycles of pharmaceuticals, efforts are still insufficient to develop analytical systems for detailed dynamic visualization of foreign substances and material composition in target pills.

Although spectroscopies, expected for pharma testing, have faced technical challenges in in-line setups for bulky equipment housing, this work demonstrates compact dynamic photo-monitoring systems by selectively extracting informative irradiation wavelengths from comprehensive optical references of target pills.

This work develops a non-destructive in-line dynamic inspection system for pharma agent pills with carbon nanotube (CNT) photo-thermoelectric imagers and the associated ultrabroadband sub-terahertz (THz)¨Cinfrared (IR) multi-wavelength monitoring.

The CNT imager in the proposed system functions in ultrabroadband regions over existing sensors, facilitating multi-wavelength photo-monitoring against external sub-THz¨CIR-irradiation.

Under recent advances in the investigation of functional optical materials (e.g., gallium arsenide, vanadium oxide, graphene, polymers, transition metal dichalcogenides), CNTs play advantageous leading roles in collectively satisfying informative and efficient photo-absorption and solution-processable configurations for printable device fabrication into freely attachable thin-film imagers in pharmaceutical monitoring sites.

The non-destructive dynamic monitoring system maintains in-line experimental setups by integrating functional thin-film imager sheets and compact multiple photo-sources.

Furthermore, permeable sub-THz¨CIR-irradiation, which provides different transmittance values specific to non-metallic materials per wavelength or composition, identifies constituent materials for pharmaceutical agents and concealed foreign substances in a non-contact manner.

This work finally inspects invisible detailed features of pharmaceutical pills with the non-destructive in-line dynamic photo-monitoring system by incorporating the performance of CNT imagers and compact optical setups.

More information: In-line multi-wavelength non-destructive pharma quality monitoring with ultrabroadband carbon nanotubes photo-thermoelectric imaging scanners. Light: Science & Applications (2025). DOI: 10.1038/s41377-025-01957-0